I. Field of the Invention
This invention relates generally to devices for reducing pressure pulsations in fluid handling systems and more particularly to a new design of such a pulsation dampener whereby the life of the diaphragm used therein is extended and the overall complexity of the device is reduced.
II. Discussion of the Prior Art
Various forms of surge suppressors or pulsation dampeners are known in the art. In general, they comprise a rigid housing defining a cavity containing a partition made from an elastomeric material which seals one portion of the cavity from the other. Provision is made to allow the working fluid subject to pressure surges to enter one compartment while the other compartment is pressurized with a compressible fluid. Typical prior art arrangements are shown in the Burton U.S. Pat. No. 4,186,776, the Porel U.S. Pat. No. 4,603,711 and the Wirth et al U.S. Pat. No. 4,201,246. Each of the devices depicted in those patents suffers from a common defect. Specifically, the elastomeric diaphragm used to separate the working fluid from the pressurized chamber is subjected to repeated flexing and folding proximate the location where the diaphragm is secured to the housing or where the diaphragm is designed to invert upon shifts in pressure on opposed sides of the diaphragm. When it is considered that such pulsation dampeners or surge suppressors are intended to be used with positive displacement fluid pumps operating at high speeds and at elevated pressures, the rapid flexures of the diaphragm, including reverse bending thereof, at the above-mentioned wear points results in premature failure.
The prior art also addresses various ways of attempting to deal with this problem. For example, the bladder or diaphragm may be reinforced or contoured so as to bend or invert in a specific fashion intended to reduce the radius of curvature of the diaphragm at the point of inversion. For example, in the Burton U.S. Pat. No. 4,186,776 patent, the diaphragm is provided with an annular lip 22c for controling the bending of the diaphragm and the diaphragm is provided with a bridging disk 34 to preclude the diaphragm from becoming extruded into the inlet when the pressure in the chamber 14 exceeds the pressure in the chamber 24. Notwithstanding the provision of these features, the planar diaphragm is still subjected to significant flexures which result in molecular heating due to friction and relatively rapid failure, thus requiring frequent replacement. Also, frictional rubbing and attendant heating of the diaphragm occurs due to contact between the diaphragm on its surrounding housing.
It is a purpose of the present invention to obviate these problems while creating a surge suppressor which not only exhibits an extended mean-time-between-failure, but which is more simple in its construction than prior art systems, thus reducing its overall cost and simplifying repair when they do become necessary.